For those of my friends who are superheroes, I would strongly recommend NOT joining up, as I believe the security measures these folks have in place are not entirely reliable. (Although their section regarding postal precautions is precious.)
However, their website is keen, and you can mock some of their uniforms, names, ideologies, etc. And, of course, feel the strong tide of mingled pity and inspiration their actions might create.
http://www.worldsuperheroregistry.com/world_superhero_registry_maine.htm Note how many of them seem SCAdian...
Kinda makes ya go "hmmmm".